Data replication for a virtual networking system

ABSTRACT

Embodiments of the invention provide a method for data replication in a networking system comprising multiple computing nodes. The method comprises maintaining a data set on at least two computing nodes of the system. The method further comprises receiving a data update request for the data set, wherein the data update request includes a data update for the data set. The data set on the at least two computing nodes is updated based on the data update request received.

BACKGROUND

Embodiments of the invention relate to overlay virtual environments, andin particular, data replication for a virtual networking system.

Network virtualization using overlays use encapsulation, such as virtualextensible local area network (VxLAN) encapsulation and networkvirtualization generic routing encapsulation (NVGRE), which may besupported by hypervisor and networking vendors. To use VxLAN or NVGREencapsulation, hypervisor virtual switches are modified to support therespective overlay technology. Incompatibility with encapsulation typesmakes it necessary to use a translation gateway, which translatesbetween the different packet formats. Often the translation gateways arecommunication bottlenecks and impact communication performance.

BRIEF SUMMARY

Embodiments of the invention provide a method for data replication in anetworking system comprising multiple computing nodes. The methodcomprises maintaining a data set on at least two computing nodes of thesystem. The method further comprises receiving a data update request forthe data set, wherein the data update request includes a data update forthe data set. The data set on the at least two computing nodes isupdated based on the data update request received.

Another embodiment provides a networking system comprising one or moredata sets and multiple computing nodes. Each data set is maintained onat least one computing node. Each computing node is configured toreceive a data update request for a data set maintained on saidcomputing node, wherein the data update request includes a data updatefor the data set. The data set is updated on the computing node based onthe data update request received.

These and other features, aspects and advantages of the presentinvention will become understood with reference to the followingdescription, appended claims and accompanying figures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an example cloud computing node,in accordance with an embodiment of the invention;

FIG. 2 illustrates an example cloud computing environment, in accordancewith an embodiment of the invention;

FIG. 3 illustrates abstraction model layers of a cloud computingenvironment, in accordance with an embodiment of the invention;

FIG. 4 shows a block diagram illustrating a distributed overlay virtualenvironment for employing an embodiment of the present invention;

FIG. 5A illustrates an example cloud cluster of a cloud computingenvironment, in accordance with an embodiment of the invention;

FIG. 5B illustrates a block diagram of a node, in accordance with anembodiment of the invention;

FIG. 6 illustrates an example data request, in accordance with anembodiment of the invention;

FIG. 7 illustrates data replication for the cluster in FIG. 5A, inaccordance with an embodiment of the invention;

FIG. 8 illustrates a flowchart of an example process of data replicationfor a virtual networking system, in accordance with an embodiment of theinvention; and

FIG. 9 is a high level block diagram showing an information processingsystem useful for implementing one embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the invention provide a method for data replication in anetworking system comprising multiple computing nodes. The methodcomprises maintaining a data set on at least two computing nodes of thesystem. The method further comprises receiving a data update request forthe data set, wherein the data update request includes a data update forthe data set. The data set on the at least two computing nodes isupdated based on the data update request received. A data update for adata set is replicated on all computing nodes maintaining the data set.

Another embodiment provides a networking system comprising one or moredata sets and multiple computing nodes. Each data set is maintained onat least one computing node. Each computing node is configured toreceive a data update request for a data set maintained on saidcomputing node, wherein the data update request includes a data updatefor the data set. The data set is updated on the computing node based onthe data update request received. A data update for a data set isreplicated on all computing nodes maintaining the data set.

It is understood in advance that although this disclosure includes adetailed description of cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g. networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as Follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded, automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active consumer accounts). Resource usage canbe monitored, controlled, and reported providing transparency for boththe provider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based email). Theconsumer does not manage or control the underlying cloud infrastructureincluding network, servers, operating systems, storage, or evenindividual application capabilities, with the possible exception oflimited consumer-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication-hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forload-balancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

FIG. 1 illustrates a block diagram of an example cloud computing node10, in accordance with an embodiment of the invention. The cloudcomputing node 10 illustrated in FIG. 1 is only one example of asuitable cloud computing node and is not intended to suggest anylimitation as to the scope of use or functionality of embodiments of theinvention described herein. Regardless, the cloud computing node 10 iscapable of being implemented and/or performing any of the functionalityset forth hereinabove.

The cloud computing node 10 comprises a computer system/server 12 thatis operational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 12 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

The computer system/server 12 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. The computer system/server 12 may be practiced in distributedcloud computing environments where tasks are performed by remoteprocessing devices that are linked through a communications network. Ina distributed cloud computing environment, program modules may belocated in both local and remote computer system storage media includingmemory storage devices.

The components of the computer system/server 12 may include, but are notlimited to, one or more processors or processing units 16, a systemmemory 28, and a bus 18 that couples various system components (e.g.,the system memory 28 and the processor 16). The bus 18 represents one ormore types of bus structures, including a memory bus or memorycontroller, a peripheral bus, an accelerated graphics port, and aprocessor or local bus using any of a variety of bus architectures. Byway of example, and not limitation, such architectures include IndustryStandard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus,Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA)local bus, and Peripheral Component Interconnects (PCI) bus.

The computer system/server 12 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 12, and it includes both volatileand non-volatile media, removable and non-removable media.

The system memory 28 can include computer system readable media in theform of volatile memory, such as a random access memory (RAM) 30 and/ora cache memory 32. The computer system/server 12 may further includeother removable/non-removable, volatile/non-volatile computer systemstorage media. By way of example only, a storage system 34 can beprovided for reading from and writing to a non-removable, non-volatilemagnetic media (not shown and typically called a “hard drive”). Althoughnot shown, a magnetic disk drive for reading from and writing to aremovable, non-volatile magnetic disk (e.g., a “floppy disk”), and anoptical disk drive for reading from or writing to a removable,non-volatile optical disk such as a CD-ROM, DVD-ROM, or other opticalmedia can be provided. In such instances, each can be connected to thebus 18 by one or more data media interfaces. As will be further depictedand described below, the system memory 28 may include at least oneprogram product having a set (e.g., at least one) of program modulesthat are configured to carry out the functions of embodiments of theinvention.

The embodiments of the invention may be implemented as a computerreadable signal medium, which may include a propagated data signal withcomputer readable program code embodied therein (e.g., in baseband or aspart of a carrier wave). Such a propagated signal may take any of avariety of forms including, but not limited to, electro-magnetic,optical, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that can communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium including, but not limited to, wireless,wireline, optical fiber cable, radio-frequency (RF), etc., or anysuitable combination of the foregoing.

A program/utility 40 including at least one program module 42 may bestored in the system memory 28 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating systems, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. The program modules 42 generally carry out the functionsand/or methodologies of embodiments of the invention as describedherein.

The computer system/server 12 may also communicate with one or moreexternal devices 14 such as a keyboard, a pointing device, a display 24,one or more devices that enable a consumer to interact with the computersystem/server 12, and/or any devices (e.g., network card, modem, etc.)that enable the computer system/server 12 to communicate with one ormore other computing devices. Such communication can occur via I/Ointerfaces 22. Still yet, the computer system/server 12 can communicatewith one or more networks such as a local area network (LAN), a generalwide area network (WAN), and/or a public network (e.g., the Internet)via a network adapter 20. As depicted, the network adapter 20communicates with the other components of computer system/server 12 viathe bus 18. It should be understood that although not shown, otherhardware and/or software components could be used in conjunction withthe computer system/server 12. Examples include, but are not limited to:microcode, device drivers, redundant processing units, external diskdrive arrays, RAID systems, tape drives, and data archival storagesystems, etc.

FIG. 2 illustrates an example cloud computing environment 50, inaccordance with an embodiment of the invention. Referring now to FIG. 2,illustrative cloud computing environment 50 is depicted. The cloudcomputing environment 50 comprises one or more cloud computing nodes 10with which local computing devices 54 used by cloud consumers, such as,for example, a personal digital assistant (PDA) or a cellular telephone54A, a desktop computer 54B, a laptop computer 54C, and/or an automobilecomputer system 54N may communicate. The nodes 10 may communicate withone another. They may be grouped (not shown) physically or virtually, inone or more networks, such as private, community, public, or hybridclouds as described hereinabove, or a combination thereof. This allowscloud computing environment 50 to offer infrastructure, platforms,and/or software as services for which a cloud consumer does not need tomaintain resources on a local computing device. It is understood thatthe types of computing devices 54A-N shown in FIG. 2 are intended to beillustrative only and that computing nodes 10 and cloud computingenvironment 50 can communicate with any type of computerized device overany type of network and/or network addressable connection (e.g., using aweb browser).

FIG. 3 illustrates abstraction model layers of a cloud computingenvironment 50, in accordance with an embodiment of the invention.Referring now to FIG. 3, a set of functional abstraction layers providedby cloud computing environment 50 (FIG. 2) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 3 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided:

Hardware and software layer 60 includes hardware and softwarecomponents. Examples of hardware components include mainframes. In oneexample, IBM® zSeries® systems and RISC (Reduced Instruction SetComputer) architecture based servers. In one example, IBM pSeries®systems, IBM xSeries® systems, IBM BladeCenter® systems, storagedevices, networks, and networking components. Examples of softwarecomponents include network application server software. In one example,IBM WebSphere® application server software and database software. In oneexample, IBM DB2® database software. (IBM, zSeries, pSeries, xSeries,BladeCenter, WebSphere, and DB2 are trademarks of International BusinessMachines Corporation registered in many jurisdictions worldwide.)

Virtualization layer 62 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers;virtual storage; virtual networks, including virtual private networks;virtual applications and operating systems; and virtual clients.

In one example, management layer 64 may provide the functions describedbelow. Resource provisioning provides dynamic procurement of computingresources and other resources that are utilized to perform tasks withinthe cloud computing environment. Metering and pricing provide costtracking as resources are utilized within the cloud computingenvironment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.Consumer portal provides access to the cloud computing environment forconsumers and system administrators. Service level management providescloud computing resource allocation and management such that requiredservice levels are met. Service Level Agreement (SLA) planning andfulfillment provides pre-arrangement for, and procurement of, cloudcomputing resources for which a future requirement is anticipated inaccordance with an SLA.

Workloads layer 66 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation; software development and lifecycle management; virtualclassroom education delivery; data analytics processing; transactionprocessing; and encapsulation mapping and communication. As mentionedabove, all of the foregoing examples described with respect to FIG. 3are illustrative only, and the invention is not limited to theseexamples.

It is understood all functions of the present invention as describedherein can be tangibly embodied as modules of program code 42 ofprogram/utility 40 (FIG. 1). However, this need not be the case. Rather,the functionality recited herein could be carried out/implemented and/orenabled by any of the layers 60-66 shown in FIG. 3.

It is reiterated that although this disclosure includes a detaileddescription on cloud computing, implementation of the teachings recitedherein are not limited to a cloud computing environment. Rather, theembodiments of the present invention are intended to be implemented withany type of clustered computing environment now known or laterdeveloped.

Embodiments of the invention relate to providing interoperabilitybetween hosts supporting multiple encapsulation. One embodiment includesa method that includes mapping packet encapsulation protocol typeinformation for virtual switches. Each virtual switch is associated withone or more virtual machines (VMs). In one embodiment, it is determinedwhether one or more common encapsulation protocol types exist for afirst VM associated with a first virtual switch and a second VMassociated with a second virtual switch based on the mapping. In oneembodiment, a common encapsulation protocol type is selected if it isdetermined that one or more common encapsulation protocol types existfor the first virtual switch and the second virtual switch. A packet isencapsulated for communication between the first VM and the second VMusing the selected common encapsulation protocol type.

FIG. 4 shows a block diagram illustrating a distributed overlay virtualenvironment 400 for employing an embodiment of the present invention. Inone embodiment, the distributed overlay virtual environment 400 maycomprise a distributed overlay virtual Ethernet (DOVE) network system.The distributed overlay virtual environment 400 includes multiplevirtual systems (or networks) 405 (also known as DOVE modules in oneembodiment) each comprising a server 310 (or host) with a virtual switch315, hypervisor 316 and VMs 320, which overlay a physical layer 325(e.g., including physical hardware and software processes) that mayinclude physical switches, routers, servers, gateways, firewalls, etc.The physical layer 325 may also be referred to as the under layer. Inone embodiment, overlay network segments 1-N 305 (e.g., overlay networksegments 1-3) connect the multiple systems for communication of thedifferent elements (e.g., hypervisors 316, VMs 320), where N is apositive number (e.g., 2, 3, 5, 10, etc.). It should be noted that whilethree systems 405 are shown, more (or less) systems 405 may be includedin the distributed overlay virtual environment 400. In one embodiment,the virtual switches 315 comprise DOVE switches.

In one embodiment, the overlay network segments 1-N 305 create overlaynetworks between the hypervisors 316 and use encapsulation of packets,where packets originating from one VM 320 are encapsulated (e.g., addingoverlay and physical network headers) and the physical layer 325(underlay) is used to deliver to a server 310 where the target VM 320resides. In one embodiment, in the physical layer 325 an outer header isused by physical switches to forward packets, where an overlayidentification (ID) in an encapsulation header provides trafficisolation. Incoming packets to a virtual switch 315 of a destinationserver 310 are decapsulated (e.g., the encapsulation headers arestripped from the packet) and delivered to a destination VM 320. In oneembodiment, address independence between different virtual systems 405is supported. For example, two different VMs 320 operating in twodifferent systems 405 may have the same Internet Protocol (IP) addressand media access control (MAC) address. As another example, the systems405 support deploying VMs 320, which belong to the same system 405, ontodifferent hosts that are located in different physical subnets (includesswitches and/or routers between the physical entities). In anotherembodiment, VMs 320 belonging to different systems 405 may be hosted onthe same physical host. In yet another embodiment, the systems 405support VM 320 migration anywhere in a data center without changing theVM 320 network address and losing its network connection.

In one embodiment, the systems 405 encapsulate data with physical pathtranslations based upon policies (e.g., from a distributed policyservice (DPS)), and send the encapsulated data between systems 405 that,in turn, is decapsulated and forwarded to a destination VM 320. In oneembodiment, the policies describe, in a logical manner, how data isrequired to be sent over virtual networks without details of theunderlying physical entities that performs particular tasks.

In one embodiment, the hypervisors 316 (e.g., VM 320 managers) allowmultiple operating systems (e.g., VMs, such as VMs 320) to runconcurrently on a host computer. A hypervisor 316 provides abstractionof physical resources to the VMs 320. For example, a physical networkinterface card (NIC) may be abstracted as a virtual NIC (vNIC) of asystem 405. In one embodiment, a virtual switch 315 is a softwareabstraction of an Ethernet switch in the hypervisor 316 for providingconnectivity for VMs 320.

FIG. 5A illustrates an example cloud cluster 100 of a cloud computingenvironment 50, in accordance with an embodiment of the invention. Thecluster 100 comprises one or more nodes 10 of the cloud computingenvironment 50, such as Node A, Node B and Node C. The nodes 10 of thecluster 100 maintain data for different data sub-groups (e.g., tenants).Specifically, each node 10 of the cluster 100 maintains at least onedata set 110 (FIG. 5B) for a data sub-group.

A client device 54 may maintain data on, and/or request data from, anode 10 of the cluster 100. For example, a client device 54 may send adata update for a data set 110 to a node 10 that maintains the data set110, wherein the data set 110 is updated based on the data update. Asanother example, a client device 54 may request a data lookup of a dataset 110 from a node 10 that maintains the data set 110.

As described in detail later herein, a data set 110 for a data sub-groupmay be replicated on different nodes 10 of the cluster 100 to support adistributed data system. The nodes 10 of the cluster 100 exchangeinformation with one another to stay in sync. Therefore, when a node 10is unable to perform a data update on/satisfy a data lookup of a dataset 110, another node 10 on which the data set 110 is replicated mayperform the data update/satisfy the data lookup.

Each node 10 of the cluster 100 maintains mapping information 120 (FIG.5B) for the cluster 100. For each data sub-group, the mappinginformation identifies one or more nodes 10 of the cluster 100 that adata set 110 for the data sub-group is mapped to. Therefore, the mappinginformation maintained on each node 10 of the cluster 100 includes amapping for the node 10 (i.e., a mapping of one or more data sub-groupsto the node 10) and a mapping for each remaining node 10 of the cluster100. In one example implementation, each node 10 maintains the mappinginformation 120 as a lookup table in a system memory 28 (FIG. 1) of thenode 10A.

In one embodiment, each node 10 of the cluster 100 is embodied as aserver unit 12 (FIG. 1). For example, Node A is represented by a firstserver unit 16, Node B is represented by a second server unit 16, andNode C is represented by a third server unit 16.

FIG. 5B illustrates a block diagram of a node 10, in accordance with anembodiment of the invention. In one embodiment, each node 10 of acluster 100 further includes a data replication application module 130configured for forwarding a data replication request to at least oneother node 10 of the cluster 100.

Specifically, the data replication application module 130 of each node10 is configured to receive a data request 210 (FIG. 6) from a clientdevice 54. In one embodiment, the data request 54 includes a data updatefor a data set 110 maintained on the node 10. The data replicationapplication module 130 updates the data set 110 based on the dataupdate, and modifies the data request 210 as a data replication request220. The data replication application module 130 forwards the datareplication request 220 (FIG. 6) to all nodes 10 that maintain the dataset 110.

FIG. 6 illustrates an example data request 210, in accordance with anembodiment of the invention. In one embodiment, a data request 210 thata node 10 receives from a client device 54 comprises a packet includingone or more of the following sections: a transport header sectionincluding information identifying the node 10, a client identifier (ID)section including information identifying the client device 54, and apayload section including a data update for a data set 110 maintained onthe node 10.

The data replication application module 130 of the node 10 modifies thedata request 210 as a data replication request 220. The data replicationapplication module 130 forwards the data replication request 220 to allnodes 10 that maintain the data set 110.

In this specification, let source node denote a node 10 that forwards adata replication request, and let destination node denote a node 10 thatreceives the data replication request. In one embodiment, the datareplication application module 130 of the source node 10 modifies thetransport header section of the data request 110 to include thefollowing: a source address (i.e., the address of the source node 10), adestination address (i.e., the address of a destination node 10), asource port (i.e., the port of the source node 10), a destination port(i.e., the port of the destination node 10), and payload informationincluding data to replicate on the destination node 10.

Each node 10 that receives a data update determines whether the dataupdate was encapsulated as a data request 210 from a client device 54,or a data replication request 220 from another node 10. If the node 10receives the data update from the client device 54, the node 10 forwardsa data replication request 220 for the data update to at least one othernode 10.

FIG. 7 illustrates data replication for the cluster 100 in FIG. 5A, inaccordance with an embodiment of the invention. Node A receives a datarequest 210 from a client device 54, wherein the data request 210received includes a data update for a data set 110 maintained on Node A.The data set 110 on Node A is updated based on the data update received.

As the date update was received from a client device 54, Node A forwardsa data replication request 220 for the data update to at least one othernode 10 of the cluster 100. Specifically, based on the mappinginformation 120, Node A determines which nodes 10 of the cluster 10 alsomaintain the data set 110 (i.e., which other nodes 10 of the cluster 100that a sub-group for the data set 110 maps to). For example, Node Adetermines that Node B and Node C each maintain the data set 110. Node Amodifies the data request 210 into a first data replication request 220for Node B, and forwards the first data replication request 220 to NodeB. Similarly, Node A modifies the data request 210 into a second datareplication request 220 for Node C, and forwards the second datareplication request 220 to Node C.

Upon receiving the first data replication request 220 from Node A, NodeB replicates the data update by updating the data set 110 on Node Bbased on the first data replication request 220. If the replication issuccessful, Node B generates and sends an acknowledgement (ACK) messageto Node A. If the replication is not successful, Node B generates andsends a negative acknowledgement (NACK) message to Node A (e.g., Node Bgenerates and sends a NACK message after fixed period of time allocatedfor data replication has elapsed).

Similarly, upon receiving the second data replication request 220 fromNode A, Node C replicates the data update by updating the data set 110on Node B based on the first data replication request 220. If thereplication is successful, Node C generates and sends an ACK message toNode A. If the replication is not successful, Node C generates and sendsa NACK message to Node A.

Upon receiving an ACK message from each node 10 that Node A hasforwarded a data replication request 220 to, Node A generates and sendsan ACK message to the client device 54, signaling that the requesteddata update for the data set 110 has been completed.

In one embodiment, data replication occurs transparently to each clientdevice 54 (FIG. 2) utilizing the cluster 100. For example, the datareplication occurs without disrupting data updates and data lookups. Thedata replication also ensures that the cluster 100 consistently providesa client device 54 with requested data.

In one embodiment, Node A may also generate and send to the clientdevice 54 a list of addresses (e.g., IP addresses) of all other nodes 10(e.g., Node B and Node C) that maintain the updated data set 110. Theclient device 54 may send a future data request 210 for the data set 110to any one of the nodes 10 listed based on a particular prioritizationscheme (e.g., round robin, load balancing, security, local policy,etc.).

FIG. 8 illustrates a flowchart of an example process 250 of datareplication for a virtual networking system, in accordance with anembodiment of the invention. In process block 251, receive a data updatefor a data set. In process block 252, update the data set based on thedata update. In process block 253, determine if the data update is froma client device. If the data update is not from a client device, proceedto process block 254 where an ACK message is sent to a node from whichthe data update originates. If the data update is from a client device,proceed to process block 255 where a data replication request for thedata update is sent to at least one other node. In process block 256, anACK message is sent to the client device after receiving an ACK messagefrom each node that a data replication request was forwarded to.

FIG. 9 is a high level block diagram showing an information processingsystem 300 useful for implementing one embodiment of the presentinvention. The computer system includes one or more processors, such asprocessor 302. The processor 302 is connected to a communicationinfrastructure 304 (e.g., a communications bus, cross-over bar, ornetwork).

The computer system can include a display interface 306 that forwardsgraphics, text, and other data from the communication infrastructure 304(or from a frame buffer not shown) for display on a display unit 308.The computer system also includes a main memory 310, preferably randomaccess memory (RAM), and may also include a secondary memory 312. Thesecondary memory 312 may include, for example, a hard disk drive 314and/or a removable storage drive 316, representing, for example, afloppy disk drive, a magnetic tape drive, or an optical disk drive. Theremovable storage drive 316 reads from and/or writes to a removablestorage unit 318 in a manner well known to those having ordinary skillin the art. Removable storage unit 318 represents, for example, a floppydisk, a compact disc, a magnetic tape, or an optical disk, etc. which isread by and written to by removable storage drive 316. As will beappreciated, the removable storage unit 318 includes a computer readablemedium having stored therein computer software and/or data.

In alternative embodiments, the secondary memory 312 may include othersimilar means for allowing computer programs or other instructions to beloaded into the computer system. Such means may include, for example, aremovable storage unit 350 and an interface 322. Examples of such meansmay include a program package and package interface (such as that foundin video game devices), a removable memory chip (such as an EPROM, orPROM) and associated socket, and other removable storage units 350 andinterfaces 322 which allow software and data to be transferred from theremovable storage unit 350 to the computer system.

The computer system may also include a communication interface 324.Communication interface 324 allows software and data to be transferredbetween the computer system and external devices. Examples ofcommunication interface 324 may include a modem, a network interface(such as an Ethernet card), a communication port, or a PCMCIA slot andcard, etc. Software and data transferred via communication interface 324are in the form of signals which may be, for example, electronic,electromagnetic, optical, or other signals capable of being received bycommunication interface 324. These signals are provided to communicationinterface 324 via a communication path (i.e., channel) 326. Thiscommunication path 326 carries signals and may be implemented using wireor cable, fiber optics, a phone line, a cellular phone link, an RF link,and/or other communication channels.

In this document, the terms “computer program medium,” “computer usablemedium,” and “computer readable medium” are used to generally refer tomedia such as main memory 310 and secondary memory 312, removablestorage drive 316, and a hard disk installed in hard disk drive 314.

Computer programs (also called computer control logic) are stored inmain memory 310 and/or secondary memory 312. Computer programs may alsobe received via communication interface 324. Such computer programs,when run, enable the computer system to perform the features of thepresent invention as discussed herein. In particular, the computerprograms, when run, enable the processor 302 to perform the features ofthe computer system. Accordingly, such computer programs representcontrollers of the computer system.

From the above description, it can be seen that the present inventionprovides a system, computer program product, and method for implementingthe embodiments of the invention. The present invention further providesa non-transitory computer-useable storage medium for hierarchicalrouting and two-way information flow with structural plasticity inneural networks. The non-transitory computer-useable storage medium hasa computer-readable program, wherein the program upon being processed ona computer causes the computer to implement the steps of the presentinvention according to the embodiments described herein. References inthe claims to an element in the singular is not intended to mean “oneand only” unless explicitly so stated, but rather “one or more.” Allstructural and functional equivalents to the elements of theabove-described exemplary embodiment that are currently known or latercome to be known to those of ordinary skill in the art are intended tobe encompassed by the present claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. section 112, sixthparagraph, unless the element is expressly recited using the phrase“means for” or “step for.”

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A method for data replication in a virtualnetworking system comprising multiple computing nodes, wherein themultiple computing nodes include a first computing node, and whereineach computing node comprises a server including one or more resources,the method comprising: maintaining a first replica of a data set for atenant on the first computing node; receiving, at the first computingnode, a data request for the data set, wherein the data request includesa data update for the data set; updating the first replica of the dataset based on the data request; determining where the data requestoriginates from; in response to determining that the data requestoriginates from a client device: determining a second computing node ofthe multiple computing nodes that maintains a second replica of the dataset; modifying the data request by modifying a transport header sectionof the data request to include an address of the second computing nodeas a destination address; and forwarding the modified data request tothe second computing node to update the second replica of the data setbased on the modified data request; and in response to determining thatthe data request originates from another computing node of the multiplecomputing nodes: sending an acknowledgement message to the anothercomputing node.
 2. The method of claim 1, wherein modifying the datarequest further comprises modifying the transport header section of thedata request to further include an address of the first computing nodeas a source address.
 3. The method of claim 1, further comprising:maintaining mapping information on the first computing node, wherein themapping information identifies which one or more computing nodes of themultiple computing nodes maintains one or more replicas for the dataset.
 4. The method of claim 3, wherein the second computing node isdetermined based on the mapping information.
 5. The method of claim 4,further comprising: in response to determining that the data originatesfrom the client device: receiving a first acknowledgement message fromthe second computing node; and sending a second acknowledgement messageto the client device in response to receiving the first acknowledgmentmessage from the second computing device.
 6. The method of claim 2,wherein modifying the data request into the first data replicationrequest further comprises modifying the transport header section of thedata request to further include a first port of the first computing nodeas a source port and a second port of the second computing node as adestination port.
 7. A system comprising a computer processor, acomputer-readable hardware storage medium, and program code embodiedwith the computer-readable hardware storage medium for execution by thecomputer processor to implement a method for data replication in avirtual networking system comprising multiple computing nodes, whereinthe multiple computing nodes include a first computing node and whereineach computing node comprises a server including one or more resources,the method comprising: maintaining a first replica of a data set for atenant on the first computing node; receiving, at the first computingnode, a data request for the data set, wherein the data request includesa data update for the data set; updating the first replica of the dataset based on the data request; determining where the data requestoriginates from; in response to determining that the data requestoriginates from a client device: determining a second computing node ofthe multiple computing nodes that maintains a second replica of the dataset; modifying the data request by modifying a transport header sectionof the data request to include an address of the second computing nodeas a destination address; and forwarding the modified data request tothe second computing node to update the second replica of the data setbased on the modified data request; and in response to determining thatthe data request originates from another computing node of the multiplecomputing nodes: sending an acknowledgement message to the anothercomputing node.
 8. The system of claim 7, the method further comprising:maintaining mapping information on the first computing node, wherein themapping information identifies which one or more computing nodes of themultiple computing nodes maintains one or more replicas for the dataset.
 9. The system of claim 8, wherein the second computing node isdetermined based on the mapping information.
 10. The system of claim 7,the method further comprising: in response to determining that the datarequest originates from the client device: receiving a firstacknowledgement message from the second computing node; and sending asecond acknowledgement message to the client device in response toreceiving the first acknowledgment message from the second computingdevice.
 11. The system of claim 7, wherein modifying the data requestfurther comprises modifying the transport header section of the datarequest to further include an address of the first computing node as asource address.
 12. The system of claim 11, wherein modifying the datarequest into the first data replication request further comprisesmodifying the transport header section of the data request to furtherinclude a first port of the first computing node as a source port, and asecond port of the second computing node as a destination port.
 13. Acomputer program product comprising a computer-readable hardware storagemedium having program code embodied therewith, the program code beingexecutable by a computer to implement a method for data replication in avirtual networking system comprising multiple computing nodes, whereinthe multiple computing nodes include a first computing node, and whereineach computing node comprises a server including one or more resources,the method comprising: maintaining a first replica of a data set for atenant on the first computing node; receiving, at the first computingnode, a data request for the data set, wherein the data request includesa data update for the data set; updating the first replica of the dataset based on the data request; determining where the data requestoriginates from; in response to determining that the data requestoriginates from a client device: determining a second computing node ofthe multiple computing nodes that maintains a second replica of the dataset; modifying the data request by modifying a transport header sectionof the data request to include an address of the second computing nodeas a destination address; and forwarding the modified data request tothe second computing node to update the second replica of the data setbased on the modified data request; and in response to determining thatthe data request originates from another computing node of the multiplecomputing nodes: sending an acknowledgement message to the anothercomputing node.
 14. The computer program product of claim 13, whereinmodifying the data request further comprises modifying the transportheader section of the data request to further include an address of thefirst computing node as a source address.
 15. The computer programproduct of claim 14, the method further comprising: maintaining mappinginformation on the first computing node, wherein the mapping informationidentifies which one or more computing nodes of the multiple computingnodes maintains one or more replicas for the data set.
 16. The computerprogram product of claim 15, wherein the second computing node isdetermined based on the mapping information.
 17. The computer programproduct of claim 16, the method further comprising: in response todetermining that the data request originates from the client device:receiving a first acknowledgement message from the second computingnode; and sending a second acknowledgement message to the client devicein response to receiving the first acknowledgment message from thesecond computing device.